Prime Minister John Key says former heavyweight boxing champion Mike Tyson was granted a visa to New Zealand on a "line call" that his rape conviction was 20 years ago and he'll be in the country "for about 20 hours".

Tyson is coming to New Zealand in November as part of an Australasian speaking tour.

The 46-year-old was sentenced to six years prison in 1992 for raping 18-year-old beauty pageant contestant Desiree Washington in an Indianapolis hotel room. He served three years and continues to deny the crime.

Key today said Immigration officials also let in other people with similar convictions who were in New Zealand for short periods.

"It's a marginal call and there are always issues that have to be reflected."

A "fairly liberal" view was taken if the crime was a long time ago and there had been no further offending, he said.

"I don't have anything personally against Mike Tyson. But I have something deeply personal against people rape other people and commit crimes against women."

Key said he turned down "numerous" people for New Years or Queens Birthday honours because they had convictions for violence against women.

"I will not allow them to have that honour. I don't think that should be bestowed on someone. So it is not specific against Mike Tyson, I'm just not fond of what he's done."

Every year the honours list was checked by the police and while speeding tickets and historic drink-driving convictions were normally looked past, violence against women was not, he said.

Tyson today said he was coming to New Zealand with his family and didn't want to cause any trouble.

"I'm not going to do anything to anyone over there," he told TVNZ from Las Vegas.

"I appreciate the support out there and I mean I do love the New Zealand people."

Tyson said his one-man show "Mike Tyson: Undisputed Truth" was about his personal experiences.